| Parameter |
Value |
| Designation |
28P/Neujmin 1 |
| Type |
P |
| Perihelion (tp_cal, UTC) |
2021-03-12T01:00:53.363520Z |
| Orbit solution date (soln_date, UTC) |
2026-06-05T08:28:30Z |
| Obs used |
1228 |
| NEO |
- |
| M1 |
13.200 |
| K1 |
4.500 |
| PC |
- |
Osculating Elements
| Parameter |
Value |
| Epoch (epoch_cal, TDB) |
2019-09-01.0000000 |
| e |
0.77345394 |
| q (au) |
1.577999 |
| a (au) |
6.965466 |
| i (deg) |
14.311489 |
| Ω (om, deg) |
346.346287 |
| ω (w, deg) |
347.442917 |
| M (ma, deg) |
330.081078 |
Magnitude
Scatter + Global Linear
$$
M_a = (13.735 + 2.000\cdot 2.5\log_{10} r) + \epsilon - 2.5\log_{10}\Phi(\theta) + 5\log_{10}\Delta
$$
$$
\theta = 180^\circ - \alpha
$$
$$
\Phi(\theta) = \frac{\delta_{90} D(\theta) + 1}{\delta_{90} + 1},\quad D(\theta) = k\cdot \Phi_{HG}(\theta; g_f) + (1-k)\cdot \Phi_{HG}(\theta; g_b)
$$
$$
\Phi_{HG}(\theta; g) = \left(\frac{1+g^2}{1+g^2-2g\cos\theta}\right)^{3/2},\quad \Phi_{HG}(90^\circ)=1
$$
Model Parameters
| Parameter |
Value |
| H0 |
13.735 |
| n |
2.000 |
| gf |
0.891 |
| gb |
-0.727 |
| k |
0.939 |
| δ90 |
1.000 |
| Parameter |
Symbol |
Range |
Description |
| Absolute magnitude at 1 AU from Sun and Earth |
H0 |
-5 to 20 |
Intrinsic brightness of the comet |
| Photometric slope parameter |
n |
2 to 6 |
Rate of brightness change with heliocentric distance |
| Forward scattering asymmetry factor |
gf |
0.8 to 1 |
Degree of forward scattering |
| Backward scattering asymmetry factor |
gb |
-1 to -0.5 |
Degree of backward scattering |
| Partitioning coefficient |
k |
0.8 to 1 |
Ratio between forward/backward scattering contributions |
| Dust-to-gas brightness ratio |
δ90 |
1 to 10 |
Relative contribution of dust scattering to gas emission |
Reference: EPSC-DPS2025-160
Finding Chart
Ephemeris
| Date/Time (UTC) |
RA (J2000) |
Dec (J2000) |
Nearest HIP |
Dist from HIP (arcmin) |
| 2026-07-29 00:00 |
09:26:10.26 |
+21:43:54.2 |
HIP 46309 |
15.31 |
| 2026-07-29 12:00 |
09:26:21.52 |
+21:42:54.1 |
HIP 46309 |
13.47 |
| 2026-07-30 00:00 |
09:26:32.79 |
+21:41:54.1 |
HIP 46309 |
12.01 |
| 2026-07-30 12:00 |
09:26:44.07 |
+21:40:54.1 |
HIP 46309 |
11.08 |
| 2026-07-31 00:00 |
09:26:55.36 |
+21:39:54.2 |
HIP 46309 |
10.82 |
| 2026-07-31 12:00 |
09:27:06.67 |
+21:38:54.3 |
HIP 46309 |
11.28 |
| 2026-08-01 00:00 |
09:27:17.98 |
+21:37:54.4 |
HIP 46309 |
12.38 |
| 2026-08-01 12:00 |
09:27:29.30 |
+21:36:54.6 |
HIP 46309 |
13.97 |
| 2026-08-02 00:00 |
09:27:40.63 |
+21:35:54.8 |
HIP 46309 |
15.91 |
| 2026-08-02 12:00 |
09:27:51.97 |
+21:34:55.0 |
HIP 46309 |
18.08 |
| 2026-08-03 00:00 |
09:28:03.31 |
+21:33:55.4 |
HIP 46309 |
20.41 |
| 2026-08-03 12:00 |
09:28:14.67 |
+21:32:55.7 |
HIP 46309 |
22.86 |
| 2026-08-04 00:00 |
09:28:26.03 |
+21:31:56.1 |
HIP 46309 |
25.38 |
| 2026-08-04 12:00 |
09:28:37.39 |
+21:30:56.6 |
HIP 46309 |
27.97 |
| 2026-08-05 00:00 |
09:28:48.76 |
+21:29:57.1 |
HIP 46621 |
28.97 |
| 2026-08-05 12:00 |
09:29:00.14 |
+21:28:57.7 |
HIP 46621 |
27.71 |
| 2026-08-06 00:00 |
09:29:11.53 |
+21:27:58.4 |
HIP 46621 |
26.70 |
| 2026-08-06 12:00 |
09:29:22.91 |
+21:26:59.1 |
HIP 46621 |
25.95 |
| 2026-08-07 00:00 |
09:29:34.31 |
+21:25:59.8 |
HIP 46621 |
25.49 |
| 2026-08-07 12:00 |
09:29:45.70 |
+21:25:00.7 |
HIP 46621 |
25.33 |
| 2026-08-08 00:00 |
09:29:57.10 |
+21:24:01.6 |
HIP 46621 |
25.49 |
| 2026-08-08 12:00 |
09:30:08.50 |
+21:23:02.6 |
HIP 46621 |
25.96 |
| 2026-08-09 00:00 |
09:30:19.90 |
+21:22:03.6 |
HIP 46621 |
26.72 |
| 2026-08-09 12:00 |
09:30:31.31 |
+21:21:04.8 |
HIP 46621 |
27.74 |
| 2026-08-10 00:00 |
09:30:42.71 |
+21:20:06.0 |
HIP 46621 |
29.01 |
| 2026-08-10 12:00 |
09:30:54.11 |
+21:19:07.3 |
HIP 46621 |
30.48 |
| 2026-08-11 00:00 |
09:31:05.52 |
+21:18:08.7 |
HIP 46621 |
32.13 |
| 2026-08-11 12:00 |
09:31:16.92 |
+21:17:10.2 |
HIP 46621 |
33.94 |
| 2026-08-12 00:00 |
09:31:28.33 |
+21:16:11.8 |
HIP 46828 |
33.56 |
| 2026-08-12 12:00 |
09:31:39.73 |
+21:15:13.4 |
HIP 46828 |
31.56 |
| 2026-08-13 00:00 |
09:31:51.12 |
+21:14:15.2 |
HIP 46828 |
29.68 |
| 2026-08-13 12:00 |
09:32:02.52 |
+21:13:17.0 |
HIP 46828 |
27.97 |
| 2026-08-14 00:00 |
09:32:13.91 |
+21:12:19.0 |
HIP 46828 |
26.46 |
| 2026-08-14 12:00 |
09:32:25.30 |
+21:11:21.1 |
HIP 46828 |
25.17 |
| 2026-08-15 00:00 |
09:32:36.68 |
+21:10:23.3 |
HIP 46828 |
24.15 |
| 2026-08-15 12:00 |
09:32:48.06 |
+21:09:25.6 |
HIP 46828 |
23.43 |
| 2026-08-16 00:00 |
09:32:59.43 |
+21:08:28.0 |
HIP 46828 |
23.04 |
| 2026-08-16 12:00 |
09:33:10.79 |
+21:07:30.5 |
HIP 46828 |
22.99 |
| 2026-08-17 00:00 |
09:33:22.15 |
+21:06:33.1 |
HIP 46828 |
23.29 |
| 2026-08-17 12:00 |
09:33:33.50 |
+21:05:35.9 |
HIP 46828 |
23.92 |
| 2026-08-18 00:00 |
09:33:44.84 |
+21:04:38.8 |
HIP 46828 |
24.85 |
| 2026-08-18 12:00 |
09:33:56.17 |
+21:03:41.8 |
HIP 46828 |
26.06 |
| 2026-08-19 00:00 |
09:34:07.50 |
+21:02:44.9 |
HIP 46828 |
27.50 |